130 research outputs found

    Spin Effects in the Effective Field Theory Approach to Post-Minkowskian Conservative Dynamics

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    Building upon the worldline effective field theory (EFT) formalism for spinning bodies developed for the Post-Newtonian regime, we generalize the EFT approach to Post-Minkowskian (PM) dynamics to include rotational degrees of freedom in a manifestly covariant framework. We introduce a systematic procedure to compute the total change in momentum and spin in the gravitational scattering of compact objects. For the special case of spins aligned with the orbital angular momentum, we show how to construct the radial action for elliptic-like orbits using the Boundary-to-Bound correspondence. As a paradigmatic example, we solve the scattering problem to next-to-leading PM order with linear and bilinear spin effects and arbitrary initial conditions, incorporating for the first time finite-size corrections. We obtain the aligned-spin radial action from the resulting scattering data, and derive the periastron advance and binding energy for circular orbits. We also provide the (square of the) center-of-mass momentum to O(G2){\cal O}(G^2), which may be used to reconstruct a Hamiltonian. Our results are in perfect agreement with the existent literature, while at the same time extend the knowledge of the PM dynamics of compact binaries at quadratic order in spins.Comment: 41 pages. 1 ancillary file (wl format

    Impulsive control of nonlinear systems with impulse time window and bounded gain error

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    In this paper, we establish a new sufficient condition for the stability of impulsive systems with impulse time window and bounded gain error. The proposed result is more general and more applicable than some existing results. Finally, a numerical example is given to show the effectiveness of our result

    Defect-Driven Efficient Selective CO2 Hydrogenation with Mo-Based Clusters

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    Synthetic fuels produced from CO2 show promise in combating climate change. The reverse water gas shift (RWGS) reaction is the key to opening the CO2 molecule, and CO serves as a versatile intermediate for creating various hydrocarbons. Mo-based catalysts are of great interest for RWGS reactions featured for their stability and strong metal–oxygen interactions. Our study identified Mo defects as the intrinsic origin of the high activity of cluster Mo2C for CO2-selective hydrogenation. Specifically, we found that defected Mo2C clusters supported on nitrogen-doped graphene exhibited exceptional catalytic performance, attaining a reaction rate of 6.3 gCO/gcat/h at 400 °C with over 99% CO selectivity and good stability. Such a catalyst outperformed other Mo-based catalysts and noble metal-based catalysts in terms of facile dissociation of CO2, highly selective hydrogenation, and nonbarrier liberation of CO. Our study revealed that as a potential descriptor, the atomic magnetism linearly correlates to the liberation capacity of CO, and Mo defects facilitated product desorption by reducing the magnetization of the adsorption site. On the other hand, the defects were effective in neutralizing the negative charges of surface hydrogen, which is crucial for selective hydrogenation. Finally, we have successfully demonstrated that the combination of a carbon support and the carbonization process synergistically serves as a feasible strategy for creating rich Mo defects, and biochar can be a low-cost alternative option for large-scale applications

    A Location-Inventory-Routing Problem in Forward and Reverse Logistics Network Design

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    We study a new problem of location-inventory-routing in forward and reverse logistic (LIRP-FRL) network design, which simultaneously integrates the location decisions of distribution centers (DCs), the inventory policies of opened DCs, and the vehicle routing decision in serving customers, in which new goods are produced and damaged goods are repaired by a manufacturer and then returned to the market to satisfy customers’ demands as new ones. Our objective is to minimize the total costs of manufacturing and remanufacturing goods, building DCs, shipping goods (new or recovered) between the manufacturer and opened DCs, and distributing new or recovered goods to customers and ordering and storage costs of goods. A nonlinear integer programming model is proposed to formulate the LIRP-FRL. A new tabu search (NTS) algorithm is developed to achieve near optimal solution of the problem. Numerical experiments on the benchmark instances of a simplified version of the LIRP-FRL, the capacitated location routing problem, and the randomly generated LIRP-FRL instances demonstrate the effectiveness and efficiency of the proposed NTS algorithm in problem resolution

    Density Functional Theory Study on the Mechanism of Biochar Gasification in CO2 Environment

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    This work presents a comprehensive analysis on the CO2 gasification of miscanthus derived biochar by using combined experimental and computational methods. The empirical formula and the 2D molecular model of the biochar were proposed based on the results from elemental analysis, Fourier infrared spectroscopy, and solid-state 13C NMR spectroscopy. The density functional theory (DFT) method was used to study the conversion of biochar to gaseous products under the CO2 condition at the B3LYP/6-31G(d,p) level. The reactants, intermediates, transition states, and products during the CO2 gasification process were analyzed, and the activation energy (ΔE) of each reaction step and thermodynamic parameters (Gibbs free energy, ΔG, and enthalpy, ΔH) were obtained. By comparison of the kinetic and thermodynamic parameters of different reaction paths, it was found that the proposed path 1 and path 5 could occur spontaneously with the changes in Gibbs free energy (ΔG) being -182.6 and -170.6 kJ/mol, respectively. The order of the reaction path was path 1 < path 5 < path 3 < path 4 < path 2, in terms of the degree of difficulty. It was also found that, for the benzene ring having a ring-opening reaction, when the substituents were located in the 2 and 3 carbon atoms or the 2, 3, and 5 carbon atoms, the C-C bond between the 1 and 6 carbon atoms was more prone to homolytic reaction than that between the 1 and 2 carbon atoms

    A Review of Spatter in Laser Powder Bed Fusion Additive Manufacturing: In Situ Detection, Generation, Effects, and Countermeasures

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    Spatter is an inherent, unpreventable, and undesired phenomenon in laser powder bed fusion (L-PBF) additive manufacturing. Spatter behavior has an intrinsic correlation with the forming quality in L-PBF because it leads to metallurgical defects and the degradation of mechanical properties. This impact becomes more severe in the fabrication of large-sized parts during the multi-laser L-PBF process. Therefore, investigations of spatter generation and countermeasures have become more urgent. Although much research has provided insights into the melt pool, microstructure, and mechanical property, reviews of spatter in L-PBF are still limited. This work reviews the literature on the in situ detection, generation, effects, and countermeasures of spatter in L-PBF. It is expected to pave the way towards a novel generation of highly efficient and intelligent L-PBF systems

    Peach allergen Pru p 1 content is generally low in fruit but with large variation in different varieties

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    Background: Pru p 1 is a major allergen in peach and nectarine, and the different content in varieties may affect the degree of allergic reactions. This study aimed to quantify Pru p 1 levels in representative peach varieties and select hypoallergenic Pru p 1 varieties. Methods: To obtain monoclonal and polyclonal antibodies, mice and rabbits, respectively, were immunized with recombinant Pru p 1.01 and Pru p 1.02. The Pru p 1 levels in fruits from 83 representative peach varieties was quantified by sandwich enzyme‐linked immunosorbent assay (sELISA). nPru p 1 was obtained through specific monoclonal antibody affinity purification and confirmed by Western blot and mass spectrometry. The variable Pru p 1 content of selected varieties was evaluated by Western blot and the expression level of encoding Pru p 1 genes by quantitative polymerase chain reaction. Results: A sELISA method with monoclonal and polyclonal antibodies was built for quantifying Pru p 1 levels in peach. Pru p 1 was mainly concentrated in the peel (0.20–73.44 μg/g, fresh weight), being very low in the pulp (0.05–9.62 μg/g) and not detected in wild peach. For the 78 peach and nectarine varieties, Pru p 1 content varied widely from 0.12 to 6.45 μg/g in whole fruit. We verified that natural Pru p 1 is composed of 1.01 and 1.02 isoallergens, and the Pru p 1 expression level and Pru p 1 band intensity in the immunoblots were in agreement with protein quantity determined by ELISA for some tested varieties. In some cases, the reduced levels of Pru p 1 did not coincide with low Pru p 3 in the same variety in whole fruit, while some ancient wild peach and nectarines contained low levels of both allergens, and late‐ripening yellow flesh varieties were usually highly allergenic. Conclusion: Pru p 1 content is generally low in peach compared to Pru p 3. Several hypoallergenic Pru p 1 and Pru p 3 varieties, “Zi Xue Tao,” “Wu Yue Xian,” and “May Fire,” were identified, which could be useful in trials for peach allergy patients.info:eu-repo/semantics/publishedVersio
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